Transmitter tape control device



y J. A. SPENCER 2,160,463

TRANSMITTER TAPE CONTROL DEVICE Filed Sept. 17, 1936 2 Sheets-Sheet 1 I INVENTOR JAMES A SP NCER A'lTRNEY May 30, 1939.

J. A. SPENCER TRANSMITTER TAPE CONTROL DEVICE Filed Sept. 17, 1936 2 Sheets-Sheet 2 INVENTOR JAMEZSPENCER BY IATI'ORNEY Patented .Mt 'so. 1939 1 UNITED STATES PATENT OFFICE Radio Corporation of of Delaware America, a corporation Application September 17, 1986, Serial No. 101,227

9 Claims. (CL 178-17) This invention relates to telegraph transmitting systems and more particularly to a transmitter employing a perforated tape for automatic code signal transmission.

As is well known, when employing tape transmitters a keyboard operated perforator is usually provided adjacent the transmitter itself. The traffic signals are stored in the tape at the convenience of the keyboard operator. The. transmitter is then enabled to transmit the signals at a constant rate provided there is sufilcient tape perforated in advance to keep the transmitter running continuously.

Devices are known in the art whereby the transmitter may be stopped at any time when the slack portion of the tape between the transmitter and the perforator has been taken up. U. 8. Patent 1,192,171 issued July 25, 1916, to A. F. Dixon, may be mentioned as disclosing such a device. The improvements to be hereinafter set forth relate more particularly to a structure suitable for use in connection with an automatic tape transmitter and so controlled by the transmitter in cooperation with the take-up device which the perforated tape controls that the transmitter will not be stopped in the midst of transmission of a character signal but only upon completion of a cycle of operation.

It is an object of my invention to provide an improved control system for stopping and starting the feed mechanism of a perforated tape transmitter, while permitting the transmitter motor and the driving connection therewith to continue running. I Other objects and advantages of my invention will become apparent as the description of the cal invention itself is setforth in the following part of the specification, wherein reference will be made to the accompanying drawings.

In the drawings, Figure 1 shows diagrammatically certain of the mechanical elements forming part of an automatic tape transmitter. these elements being set out distinct from other well known portions of the transmitter itself in order that the invention may be more clearly understood;

Fig. 2 shows a modification of the invention by means of an elevation view looking at the transmitter from the side; and I Fig. 3 shows another view in elevation of the same modification as that of Fig. 2, but looking at-thedevice from the front end.

Referring first to Fig. 1 the transmitting mechanism includes a ratchet-wheel I mounted on the 55 same shaft with a sprocket wheel (not shown).

' the latter being adapted to feed the perforated tapeT in the direction shown by the arrows. The ratchet wheel is rotated step-by-step by means of a pawl 2 mounted on the upper end of vertical bar 21. At the lower end of the bar 5 21' is a threaded stud 38 carrying nuts 35 for adjusting the amount of'elevation of the rod 21 under control of a yoke member 18. The right hand end of the yoke member It supports one of the nuts 35 while the othernut is used for locking purposes. When the rod 21 is permitted to be lowered by the action of the rocker arm 18 and by the contraction of the spring 34, then the pawl 2 will ride over a tooth of the ratchet wheel and be in position for advancing the tape one step during the next cycle of operation of the transmitter.

The tape feed function of the rocker arm II is. conventional in transmitters of this type. With each cycle of operation of the transmitter the tape is fed forward for detecting successive transverse arrays of code perforations. This cycle of operation will now be described merely for the purpose of showing the relationship between certain of the moving elements of a conventional transmitter with the improvements for which novelty is herein claimed.

The transmitter is provided with a drive shaft. 20 which, for convenience, has been shown in cross section in two parts of the drawings, although it will be understood that in the apparatus itself there need be only one such shaft 26 upon which different cams 9 are mounted for controlling the contacts 25 through the lever arms III. A single cam l2 is also provided for controlling the tape feed mechanism.

The device as viewed in Fig. 1 isarranged so that the shaft 26 will be rotated counter-clockwise. A motor (not shown) runs the shaft 26 continuously. Where the transmitter is used for teletype code signaling there are usually provided five different cams 9 each operating an individual lever arm in for controlling the moments of closure of the contacts 25, sequentially with respect to the five elements of the code signal.

The upper contact 25 connects with a contact i which is adapted to be set either against a marking contact 5 or a spacing contact 4, ac-

cording to the perforations in the tape. The set- Upon com'pletion of the transmission of a code 7 signal, it being understood that during the transmission certain of thepins 8 were permitted to project through perforations in the tape T, these pins 3 are then withdrawn downwardly under control of a member I! which is mounted on a' rocking member 31 pivoted at l1. The member 31 has a lug projecting to the left for engagement with the head of a screw it carried by the lever arm ii. The lever II is pivoted at 33 and operates under control of the cam l2. A cam follower 32 is mounted on the lever arm II and is positioned against the face of the cam I2 sofas to be raised and lowered according to the cam contour.

As the cam l2 rotates and during substantially one complete revolution lever arm ll lifts the lug on the member 31, rotates this member clockwise, and pulls down the catch arm 19, which in turn pulls down the pecker-pins 3 out of engagement with the tape '1".

The member 31'carries another arm projecting to the right and supporting a lug 3|, the function of which is to engage with the left hand end of the rocker arm l8, thereby to lower that end while lifting the rod 21 for actuating the tape feed mechanism to advance the tape one step.

The apparatus thus far described is more or less conventional. The description is herein presented in order to show the utility of the elements of structure alleged to be novel. I will now describe the novel elements of the structure and the manner in which they co-operate with the well-known transmitter..

The device for arresting the tape feed mechanism comprises magnet whose armature i4 is pivoted at 38 and is connected by a pivot screw 39 with a lever arm it. This lever arm i3 is also pivotally connected .at 40 to a rotatable member 2i which swings on the pivot center I. The lever arm l3 extends also to the left where it is provided with lugs- 42 for engagement with the contact spring C. Normally contact springs C and A are in engagement with each other, but when the magnet 20 is energized contacts C' and A- are opened and contacts B and C are closed. As a result the polarity of the contacts 4 is shifted from-negative to positive and the transmitter becomes inactive for signaling purposes. v I

If the magnet 20 is energized during the transmission of a code signal its armature cannot be fully drawn up because of an interfering action between the member 2i and a projecting lever arm 28, the latter being mounted as a bracket on the rocker member 31. Previous to the moment of initiating a signal the member 31 has been rotated counter-clockwise thereby elevating the right end of the bracket member 28, so that it engages with a stop 2la on the lever arm 2|. This prevents the full movement of the lever arm 2| and of the other elements with which it is connected, including member l3 and the armature it. When, however, the signal transmission has been completed, the cam l2 rotates so as to lift the lever i l, swing the rocking member 31 clockwise and lower the bracket member 20 so that it slips 'below the bottom edge lib of the stop 2la. At that instant the magnet 22 attracts its armature to the limiting position and causes the member 2l-,to be restrained by the stop '2la from further action. Continued raising and lowering of the lever arm II is not prevented, however, because it is usually not. desirable to stop .the motor for short periods 'of time.

It will be seen from the above description that the transmission of signals can be arrested by the actuation of the magnet 2| but without disturbing the synchronous rotation of the drive shaft 26.

The magnet 20 is in circuit with contact strings 22, the closing of which is accomplished by means of a lever arm 29 on one end of which is mounted a roller 23 and on the other end of which is a finger 29! adapted to engage with and be controlled by the perforated tape T. The ilnger 2!) is lifted whenever the tape becomes taut due to failure of the perforator keyboardoperator to keep' the transmitter supplied with suflicient tap for continuous operation.

With renewed operation of the perforator sufficient slack is provided in the tape so that the lever arm 28 may be caused to open up the contacts 22. The magnet 20 then releases its armature and the transmitter resumes its operation of sending out signals. During the time that the transmitter was stopped its motor (not shown) was maintained in synchronism with the multiplex system as a whole. Starting and stopping of the transmission on any one channel may, therefore, be accomplished without diillculty, and the signals are always "phased in with the transmission of signals on other multiplex channels.

It will be understood by those skilled in the art that my invention is applicable not only ,to printing telegraph code transmitters but also to tape transmitters utilizing any other code, including Morse.

Referring now'to Figs. 2 and 3, I show a modification of the invention in which, under certain the pivot center 54. The operating means for I moving the pawl up and down comprises a rocker arm pivoted at 58 and having one end in engagement with the downwardly extending leg of the lever member 53. The lower end of the rocker arm 55 carries an adjusting screw 51 which engages with an oscillating member ll. i

The means for actuating the member 58 are not shown in detail, but it may be well understood that any suitable cam. such as the cam i2 shown in Fig. 1, may be utilized in co-operation with a cam follower such as 32 in Fig. 1 thereby to provide a longitudinal movement'of the bar II for actuating the rocker arm. This operates the tape feed mechanism. a

This tape feed mechanism, according to my invention, may be locked against operation whenever the slack in the tape T is taken up. In this case a magnet 20a is provided for performing the same function as the magnet 2| in Fig. 1. The armature 66 is pivotally mounted on a shaft 1|.

Cal

The spacing of the armature from the pole piece of the magnet 200, may be adjusted by means of the screw 16.

The extremity of the armature 66 is adapted to engage with a catch 61 mounted on the rocker arm 55. If the rocker arm 55 is in the position as shown in Fig. 2 when the magnet 20a becomes energized, then the armature 66 is prevented from being fully drawn up to the pole piece of the magnet. The motion of the, rocker arm will not, therefore, be arrested until it has been rotated in a counter-clockwise direction so as to withdraw the catch 61 from the underside of the armature. When, however,the rocker arm has completed this stroke the armature will be pulled down still further and thus will lock the rocker arm 55 against further actuation. The oscillating member 58 may continue to go through its motions, but

it will have no effect upon the rocker arm 55 which has now been locked in a position out of reach of the member 58.

At times it may be desired to stop the operation of the transmitter manually and without recourse to the tape control as provided by the take-up detector 29 (Fig. 1). Accordingly I provide a manual lever mounted on a shaft 65 and pivoted in the bearing 68. The shaft 65 has keyed thereto a lever 12 at the end of which is a pin 13 for supporting one end of a spring S. The other end of this spring is retained by a pin 14 mounted on the armature 66. The two shafts 65 and 15 are co-axial. When the transmitter is to be maintained under control of the tape slack the manual lever 10 will be positioned so that the rear end of the spring S occupies position I. This position is such that the armature 66 is urged upwardly against the adjusting screw 16 but can be pulled down against the tension of'the spring by energizing the magnet 20a. When, however, the manual lever arm 10 is rotated so as to put the pin 13 in position II, then the armature 66 is constantly urged downwardly and the same effect is obtained as though the magnet 20a were energized. The transmitter is, therefore, stopped as long as the manual lever 10 remains in this position.

It will be understood by those skilled in the art that numerous modifications of my invention may be made without departing from the spirit and scope of the invention itself.

I claim:

1. In a tape controlled transmitter, a perforated tape, a tape feed mechanism, a code signaling mechanism operable under control of said tape, means including a motor for driving said feed mechanism and said code signaling mechanism synchronously, an intermittently operable tape perforator for delivering a slack portion of said tape to said transmitter, a take-up detecting device engageable with said slack portion of the tape, magnetic means operable under control of said take-up detecting device when the tape becomes taut for disengaging said tape feed mechanism from said driving mechanism, and means operative while said tape feed mechanism is disengaged for maintaining the code signaling mechanism in driven connection with said motor.

2. A tape feed mechanism for a telegraph transmitter in combination with a motor for driving the same at a constant cyclic rate, a transmitting tape, a tape controlled signaling mechanism adapted to be constantly driven by the same motor, means operable at an irregular speed for delivering said tape to said feed mechanism, means including a magnet for rendering said tape feed mechanism inoperative, means for maintaining said signaling mechanism at all times in driven connection with said motor, and means controlled by the relative speeds of delivery and take-up of said tape for energizing said magnet.

3. A telegraph transmitter having a tape operated code signaling device, means including a plurality of switching mechanisms for connecting different elements of the code signaling device successively witha line, motor driven means for continuously actuating the switching mechanisms of said transmitter at a uniform speed, means including a perforated tape for controlling said code signaling device, means for intermittently feeding said tape at a constant cyclic rate, means operable at an indefinite speed for perforating said tape with code signals and for delivering said tape to said feeding means, electromechanical means operable by said tape when a portion thereof between the perforating means and the feeding means becomes taut for arresting the action of said feeding means, and means enabling the actuation of the switching mechanisms to be continued during inaction of the tape feeding means.

4. In a telegraph transmitter having code signal impulse sending mechanism and a perforated tape for controlling said mechanism, a tape feeding device, driving means for continuously actuating said mechanism and for intermittently actuating said device, means for operably engaging said tape feeding device with and disengaging the same from said driving means, means including a magnet for operating the engaging and disengaging means during a particular moment in the cycle of operation of said impulse sending means, and means controlled by the tape for energizing said magnet.

5. A device according to claim 4 and having a switch for altering the effects of said impulse sending mechanism, said switch being under control of said magnet.

6. A device according to claim 4 and having a manually controlled means auxiliary to said magnet for operating said engaging and disengaging means.

7. A telegraph code signaling device in combination with a perforated tape for controlling the same, a tape feeder, means for continuously and cyclically mechanically actuating said device and for cyclically and intermittently actuating said feeder, electro-mechanical means under control of the tape for disabling said feeder and means effective to maintain a cyclic rate of actuation of said device irrespective of the actuation or disabling of said feeder.

8. A telegraph code transmitter comprising a plurality of sequentially operable contact members connectable to a' line, a cam-and-follower mechanism for continuously and periodically actuating said members, a code signaling device having a plurality of switches for selectively applying positive and negative potentials to said contact members, a perforated tape, a tape feeding device and perforation-sensing means for controlling the actuation of said code signaling device, means for at times synchronizing the operation of said switches, tape feeding device and perforation-sensing means with the operation of said contact members, the last said means having driving connections including a cam-and-follower operable in unison with the first said cam-andfollower mechanism, and electro-mechanical means including a magnet and a tape-tension feeler in association with a closable circuit to said magnet for at times disengaging the code signaling device and the tape feeding device from their driving connections in accordance with the tape tension.

9. In a system for transmitting telegraph code si nals by actuation of a signal impulse sending mechanism under control of a perforated tape. the method of starting and stopping the sending operation which includes feeding said tape In through the sending mechanism at a cyclic rate,

supplying said tape a given source at an irregular rate, causing a predetermined amount of slack in the tape to be-eiiective in maintaining 'said. cyclic rate of tape teed. causing a condition of tape-slack-deflciency to be elective in arresting said cyclic rate of tape teed.'and causing said signal impulse sending mechanism to be actuated continuously at said cyclic rate irrespective of the starting and stopping of said tape feed.

James A. smmbm, w 

